Twenty-nine patients fitting the NINCDS-ADRDA criteria of Alzheimer's disease participated in a study of autonomic functions. A number of tests on parasympathetic and sympathetic functions were made. Eighteen of the patients were tested a second time one year later. Fifteen healthy subjects with no family history of dementia disorders served as controls. Compared to the controls, the patients showed signs suggesting autonomic dysfunction affecting parasympathetic, as well as vasomotor sympathetic, functions.